Tactile graphics are used primarily by the blind and sight-impaired because they allow for tactile sensing. In general, tactile graphics refer to any graphics being communicated via media that allow for tactile sensing. Tactile drawings, also called raised line drawings or RLD's, are tactile graphics created by freehand drawing or sketching on specialized media.
With reference to FIG. 1, tactile drawings are formed in one example by a stylus 10 that is pressed into and moved relative to the surface 21 of a locally deformable medium 20, also referred to herein as a “tactile drawing medium.” The tactile drawing medium 20 permanently or semi-permanently supports one or more tactile features 30 when pressure is applied by the stylus. In particular, as stylus 10 is moved across and is pressed into surface 21 of deformable medium 20 by a user (not shown), a tactile feature 30 is formed thereon, with the tactile feature being representative of the stylus path.
A typical tactile drawing medium 20 comprises a thin plastic sheet, which is placed and secured (e.g., via a clip 40, as shown) on top of a pad of flexible or indentable material 24, such as rubber. Stylus 10 can be a typical ballpoint pen or the like. The force of stylus 10 on the flexible material 24 through tactile drawing medium 20 locally indents and stretches the tactile drawing medium, which responds by rising into positive relief to create a tactile feature 30. This system has the benefit of letting a user feel what they are drawing while they draw it, and provides a permanent hardcopy of their tactile drawing that others can tactilely sense.
To date there is no practical means for readily reproducing tactile drawings or forming non-tactile copies from tactile drawings. There exists methods for creating or even reproducing some forms of tactile graphics; i.e. printers that print tactile graphics, e.g. Braille graphics printers and thermoform “toasters”. A major difference is that the media on which these devices print is not interactive, meaning that a human user cannot add to or edit the graphics. Such tactile graphics cannot be created and sensed tactilely at the same time, and thus are generally not employed by blind users who wish to communicate graphically. In contrast, tactile drawings allow a user to create and tactilely sense graphics in real-time.